HAZOP: Hazard and Operability

What is HAZOP?

Hazard and Operability (HAZOP) is a systematic approach to identifying potential problems and issues within complex systems. This structured method is used to uncover safety risks and process inefficiencies by examining both new designs and existing operations. HAZOP studies are particularly crucial in high-risk industries such as chemical manufacturing, pharmaceutical production, oil and gas processing, and nuclear power generation.

Purpose

HAZOP, also known as HAZOP study or HAZOP analysis, is a Process Hazard Analysis (PHA) method recognized in OSHA’s Process Safety Management (PSM) standard. It is a form of risk management to identify, evaluate, and control hazards and risks in complex processes. It involves highly hazardous chemicals that can cause significant injuries to workers and extensive damage to property and company reputation if not properly processed and handled. It helps the organization address:

• potential hazards in business operation;

• past incidents that had likelihood for catastrophic consequences;

• human-controlled factors; and

• consequences of failure of applied control measures including the range of the possible health and safety risks.

Importance

HAZOP is a risk assessment approach that has become the de facto industry standard. It is a highly structured method of analyzing any possible deviation that can happen in a complex plant including chemical, pharmaceutical, oil and gas, nuclear, and mining industries. It is a crucial task that helps multiple industries to:

• proactively catch hazards and help formulate risk mitigation early on during the planning or design stage of projects;

• realize risks during modification of current processes and see how deviations may occur from the design intent; and

• investigate how the plant or systems deviate from business goals that create a risk to personnel and operation.

The Difference Between HAZOP, Risk Assessment, and HAZID

While risk assessments, HAZID, and HAZOP all aim to uncover safety risks in the workplace, there are differences.

HAZOP Study Process

As HAZOP undertakes the careful review of complex processes involved in the handling and processing of chemicals and materials that can potentially harm workers and stakeholders if not properly contained and handled, it is important to follow the following steps:

1. Build a HAZOP team

Create a multidisciplinary HAZOP team composed of a team leader and members who can collaborate and provide different perspectives based on their fields of expertise at realizing sources of risks and possible deviations from design. An example of HAZOP team members would be design engineers, those who are very familiar with operations, and safety professionals.

2. Identify processes, P&ID, and HAZOP nodes

When beginning a HAZOP study, it is important to identify the processes in operations, be familiar with the process/piping and instrumentation diagram (P&ID), and be aware of all the nodes.

P&ID are drawings or diagrams that provide the visual representation of interconnected processes, equipment, and controls in the physical plant. HAZOP nodes are sections in the entire process where changes happen and they need to be reviewed along with Material Safety Data Sheets (MSDS) so that parameters can be defined and deviations are identified.

Safety Data Sheet Template

Use this SDS template when identifying chemicals and other materials’ properties that can pose hazards to workers. Completed SDS in Mitti (by SafetyCulture) can be easily retrieved during HAZOP reviews.

3. Define the parameters, determine deviations, and select guide words

Define parameters or safe operating limits during the review of nodes so that deviations can be determined and guide words are selected.

Examples of common HAZOP guide words:

• No or not

• More

• Less

• High

• Low

With the use of guide words, workplace hazards can be clearly identified as they are the deviations that go beyond acceptable parameters or safe operating limits.

4. Identify controls and establish safety monitoring

With hazards identified, the corresponding hazard mitigation or elimination strategies should be applied to maintain the safety of the workplace. With ongoing processes and production, monitoring should also be established to ensure that safeguards are still effective and safety procedures are being followed.

Monitoring is only effective when it is conducted regularly. With Mitti (by SafetyCulture) as mobile safety monitoring software, you can ensure that safety checks and audits are conducted regularly through scheduled inspections and automated notifications. Administrators can schedule and assign inspections and be made aware if inspections are indeed being done on time and on a regular basis. Register here for free.

Another safeguard is to automate safety monitoring through sensors. Sensors can trigger automated notifications for intended personnel whenever safety parameters are exceeded in real-time.

5. Communicate HAZOP results and improve processes

The result of the HAZOP analysis can be used to help elevate safety within the plant and improvements in safety practices and processes should be communicated to as appropriate to employees e.g. occupational safety, chemical safety and hygiene safety processes.

An effective approach to safety training or program will also help hasten the implementation of changes and reinforce safety across the board.

4 Phases of HAZOP Analysis

A HAZOP analysis is conducted by a suitably experienced multi-disciplinary team to thoroughly examine a planned or existing process. It helps identify and evaluate health hazards that may endanger people or hinder efficient operation of the business. A HAZOP analysis is executed in four phases, as follows:

1. Definition Phase

The definition phase typically begins with the preliminary selection of risk assessment team members. After building the team, they must clearly define their responsibilities and identify their objective and assessment scope including study boundaries, key interfaces, and assumptions.

2. Preparation Phase

During the preparation phase, the team should identify and locate supporting data and information to plan the study. They have to prepare the schedule, timelines, and template format for recording study outputs.

3. Examination Phase

The examination phase begins with the identification of all elements such as parts or steps of the system or process to be examined. The team has to classify deviation using guide words on each element and identify consequences and causes of problems. They have to establish protection, detection processes, and supporting mechanisms.

4. Documentation and Follow-up Phase

The documentation and follow-up phase utilizes HAZOP templates to finalize the output reports. It involves the review of recorded examinations, follow-up on implemented action plans, and re-study of any system parts if necessary before signing off the documentation.